In order to process a plurality of jobs in parallel, it is necessary for each job to secure a minimal memory.
On the other hand, even if the image-input-to-box function is executed, the box-to-image-output function is not necessarily executed in a moment. Therefore, it is necessary to release an acquired memory.
However, when executing the box-to-image-output function, if the content of the document file is not read from the box once and analyzed, it is difficult to determine how large a memory size necessary at the time of image-outputting, such as printing. Therefore, when starting the job, it is necessary to secure memory having a supposed and fixed maximum size for image process one page.
On the other hand, if the above-described analysis is performed, the process is delayed and the performance of the image forming apparatus is reduced.
As seen from the above, even if the data size corresponding to one page is a local minimum, the memory of a maximum size is secured. Therefore, a waste of memory area occurs. In particular, when the size of the memory installed in the image forming apparatus is small, there is a possibility that available memory does not exist and processing the plurality of jobs in parallel is disturbed.